Modeling Magnetic, Electric, and Acoustic Fields of a Pass-Through Transducer When Testing Cylindrical Objects

We present results of numerically modeling the magnetic, electric, and acoustic fields of a pass-through EMA transducer of longitudinal waves by the finite element method in the COMSOL Multiphysics software environment. The main approaches used in the modeling are described. The influence of structural gaps between the EMA transducer and the test object on the magnitude and distribution of eddy current density, as well as the main and interfering components of a bias field have been investigated. The influence of operating frequency on acoustic field parameters has been analyzed. Recommendations are given on the choice of transducer’s operating frequency and probing-pulse quality factor needed to shape the required diagram of displacements relative to the object diameter and to assess the sensitivity to surface and internal defects located at different depths.